diff --git a/Package.swift b/Package.swift
index 2ed9ccce95..48351519b6 100644
--- a/Package.swift
+++ b/Package.swift
@@ -1,4 +1,4 @@
-// swift-tools-version:5.6
+// swift-tools-version:5.9
 // The swift-tools-version declares the minimum version of Swift required to build this package.
 
 import PackageDescription
@@ -6,9 +6,9 @@ import PackageDescription
 let package = Package(
     name: "Then",
     platforms: [
-        .iOS(.v9),
-        .macOS(.v10_12),
-        .tvOS(.v10),
+        .iOS(.v12),
+        .macOS(.v10_13),
+        .tvOS(.v12),
         .watchOS(.v6)
     ],
     products: [
diff --git a/Tests/ThenTests/RegisterThenTests.swift b/Tests/ThenTests/RegisterThenTests.swift
index 8b3b5469b4..730eb1d1a1 100644
--- a/Tests/ThenTests/RegisterThenTests.swift
+++ b/Tests/ThenTests/RegisterThenTests.swift
@@ -68,15 +68,15 @@ class RegisterThenTests: XCTestCase {
         
         let thenExpectation = expectation(description: "thenExpectation")
         fetchUserId()
-            .registerThen { _ in
+            .registerThen { _ -> Void in
                 XCTAssertTrue(count == 0)
                 count+=1
                 block1.fulfill()
-            }.registerThen {_ in
+            }.registerThen {_ -> Void in
                 XCTAssertTrue(count == 1)
                 count+=1
                 block2.fulfill()
-            }.registerThen {_ in
+            }.registerThen {_ -> Void in
                 XCTAssertTrue(count == 2)
                 count+=1
                 block3.fulfill()
@@ -155,26 +155,28 @@ class RegisterThenTests: XCTestCase {
         
         let thenExpectation = expectation(description: "thenExpectation")
         fetchUserId()
-            .registerThen { _ in
+            .registerThen { _ -> Void in
                 XCTAssertTrue(count == 0)
                 count+=1
                 block1.fulfill()
-            }.registerThen {_ in
+            }.registerThen {_ -> Void in
                 XCTAssertTrue(count == 1)
                 count+=1
                 block2.fulfill()
-            }.registerThen {_ in
+            }.registerThen { _ -> Void in
                 XCTAssertTrue(count == 2)
                 count+=1
                 block3.fulfill()
-            }.then { name in
+            }
+            .then { name in
                 XCTAssertTrue(count == 3)
                 count+=1
                 print("name :\(name)")
                 thenExpectation.fulfill()
-            }.then { _ -> Void in
+            }
+            .then { _ -> Void in
                 print("Just another then block")
-        }
+            }
         waitForExpectations(timeout: 0.3, handler: nil)
     }
 
diff --git a/Tests/ThenTests/ThenTests.swift b/Tests/ThenTests/ThenTests.swift
index 7ed287a626..280e08153a 100644
--- a/Tests/ThenTests/ThenTests.swift
+++ b/Tests/ThenTests/ThenTests.swift
@@ -20,7 +20,7 @@ class ThenTests: XCTestCase {
         fetchUserId()
         .then(fetchUserNameFromId)
         .then(fetchUserFollowStatusFromName)
-        .then { isFollowed in
+        .then { isFollowed -> Void in
             XCTAssertFalse(isFollowed)
             thenExpectation.fulfill()
         }.onError { _ in